1. Field of the Invention
This invention relates to a device for dispensing measured quantities of liquids. The device is particularly useful for dispensing medications in accurate metered quantities, either nasally or intravenously. The invention allows an end user to adjust the quantity of material dispensed in each metered dose. The invention includes a container for the material to be dispensed and a relatively movable operating device projecting outwardly of the container for dispensing the material via a pump mounted on the operating device. Because the dispensing pump is mounted on the operating device, the invention can be used with conventional containers used to hold medications for intravenous injection. One type of medication which the present invention is particularly useful for dispensing is insulin, which may be administered in accurate metered doses either nasally or intravenously with the device of the present invention. Furthermore, because the pump is not mounted in the container, it may be reused - - - requiring less waste than a conventional container with a pump which is thrown away with the container when the container is emptied.
2. Description of the Related Art
U.S. Pat. No. 3,254,803 shows a device for dispensing quantities of liquid in the form of a spray into a nasal cavity. The device of this patent uses an aerosol container mounted in a dispensing package for dispensing a metered quantity of liquid. The device of U.S. Pat. No. 3,254,803 does not, however, allow a user to select or vary the quantity of liquid delivered with each dose, since the amount delivered is dependant upon the structure of the metering valve within the aerosol container. This device also is not intended to be used with a conventional medication container, and is not adapted to allow intravenous injection.
U.S. Pat. No. 3,211,346 shows a device for dispensing liquid under the action of a pump, in which the pump is mounted to a non-vented container pressurized by a quantity of inert gas. This type of device, in which the material to be dispensed does not come into contact with air until it exits the spray head, is particularly useful for dispensing medications, which could degrade if placed in contact with the air used to vent a conventional piston-operated dispensing pump. The device of U.S. Pat. No. 3,211,346 does not contain any mechanism for limiting the length of the stroke of the pump. The only metered quantity that this pump can dispense is that quantity that comes when the pump is depressed through its full stroke. Furthermore, in this device the pump is mounted in the container, with the result that the pump is disposed of when the container is empty.
U.S. Pat. No. 5,363,992 and U.S. patent application Ser. No. 08/012,196 show mechanisms for limiting the length of stroke of a spray pump, to thereby allow the pump to dispense a number of different metered quantities of liquid material. The devices of these patent applications are designed to be used with spray pump devices which use a finger-operated reciprocating actuator, and include mechanisms whereby a conventionally-styled actuator interacts with a stroke limiting device to control the amount of liquid dispensed. These devices also include different spray nozzles for different particle sizes, with differently structured break-up devices. The devices of these patent applications are not suited for a spray nozzle which is inserted nasally, since such devices do not use a conventionally-styled actuator.
U.S. patent application Ser. No. 08/099,386, the substance of which is incorporated here in by reference, shows a device for dispensing liquids, particularly medications, nasally. This device shows a mechanism for limiting the stroke of the pump, to ensure accurate and adjustable quantities of the liquid dispensed. This device, however, uses a liquid container which includes a pump, and is therefore not useable with conventional containers for liquid medical products. Furthermore, this device can only be used to dispense liquids nasally, and cannot dispense liquids intravenously as well.